Mind your punctuation

Jenny Hogan writes:

Pluto is one of a new category of object to be known as ‘dwarf’ planets (which, not to be confusing, don’t fall under an umbrella term of ‘planets’, and must, by definition, be written with single quote marks around ‘dwarf’). These objects satisfy the other criteria, in being round and not a satellite. Ceres, which lies in the asteroid belt between Mars and Jupiter, is also now a ‘dwarf’ planet.